Alkylaromatic sulfonate detergent process

ABSTRACT

Alkylaromatic sulfonates, containing a C9-C18 linear alkyl group, are prepared by sulfonating the corresponding alkylbenzene in admixture with a C9-C18 n-paraffin and neutralizing the resultant alkylbenzene sulfonic acid, in admixture with the same paraffin, to produce a relatively colorless neutralized alkylbenzene sulfonate. This process is particularly adaptable where a C9-C18 n-paraffin stream is first converted to an alkylatable compound such as a monohalogen and such compound is not readily separable from the n-paraffin. Thus, the alkylation, sulfonation and neutralization are all performed in admixture with the unreacted n-paraffin whereby the paraffin is readily separable from the final product, for recycle purposes.

United States Patent Bloch et al.

ALKYLAROMATIC SULFONATE DETERGENT PROCESS Inventors: Herman S. Bloch,Skokie; George E.

Illingworth, Arlington Heights; George W. Lester, Park Ridge, all ofI11,

Appl. No.: 476,007

Related US. Application Data Continuation of Ser. No. 275,380, July 26,1972, abandoned, which is a division of Ser. No 787,268, Dec. 26, 1968,Pat. No, 3,681,442.

US. Cl 260/505 A; 252/558; 260/5U1.21; 260/505 N; 260/505 S; 260/512 R;260/621 lnt. CL CO7C 143/24 Field of Search 260/505 A, 505 5 *Oct. 7,1975 Primary Examiner-Joseph E. Evans Assistant ExaminerA. SiegelAttorney, Agent, or Firm.lames R. Hoatson, .lr,; Thomas K. McBride;William H. Page, ll

[57] ABSTRACT Alkylaromatic sulfonates, containing a C C,,, linear alkylgroup, are prepared by sulfonating the corresponding alkylbenzene inadmixture with a C -C nparaffin and neutralizing the resultantalkylbenzene sulfonic acid, in admixture with the same paraffin, toproduce a relatively colorless neutralized alkylbenzene sulfonate. Thisprocess is particularly adaptable where a C C,,, n-paraffin stream isfirst converted to an alkylatable compound such as a monohalogen andsuch compound is not readily separable from the n-paraffin. Thus, thealkylation, sulfonation and neutralization are all performed inadmixture with the unreacted nparaffin whereby the paraffin is readilyseparable from the final product, for recycle purposes,

2 Claims, N0 Drawings ALKYLAROMATIC SULFONATE DETERGENT PROCESS CROSS-REFERENC E TO RELATED APPLICATIONS This application is aContinuation of our copending application Ser. No. 275,380. filed July26. l972 now abandoned, which is, in turn, a Division of our copendingapplication Ser. No. 787,268, filed Dec. 26. 1968, now U.S. Pat. No.3,68 l ,442, the teachings of both of which are incorporated herein byspecific reference thereto.

BACKGROUND OF THE INVENTION This invention relates to a process for theproduction of alkylaromatic sulfonates containing a C,,C,,, linear alkylgroup. Generally, it is concerned with separating a (E -C n-paraffinfrom a hydrocarbon mixture containing the paraffin, converting saidparaffin to an olefin-acting compound. in particular, a monochlorinatedor monobrominated paraffin, alkylating with said compound, in admixturewith the unconverted paraffin. a monocyclic alkylatable aromatichydrocarbon to form an alkylaromatic hydrocarbon containing a linearC,,C alkyl group. sulfonating said alkylaromatic hydrocarbon andneutralizing the resultant sulfonic acid. both reactions in admixturewith the unconverted paraffin, separating from the neutralized product,alkylaromatic sulfonates and unconverted n-paraffin, and recycling saidparaffin to be converted into the aforementioned olefinacting compounds.Specifically, this invention relates to separating the hydrocarbon phasecontaining the unconverted paraffin and alkylaromatic sulfonate from theacid phase, formed in the sulfonation reaction and neutralizing thehydrocarbon phase, recovering therefrom n-paraffins and neutralizedsulfonic acid of excellent color quality. Further, this invention isconcerned with sulfonating an alkylaromatic hydrocarbon containing aC,,C,,, n-paraffin and neutralizing the resultant sulfonate in admixturewith the same paraffin to provide a detergent of excellent colorquality.

Processes for the production of biodegradable detergents have gainedconsiderable importance within the last few years because of the waterpollution problem, stemming in part from sewage disposal and longevityof detergents dissolved in this sewage. The presence of detergentsdissolved in the sewage is the deleterious consequence of the inabilityof bacteria to degrade the original detergents. When thesenon-biodegradable detergents are aerated. such as when the treatedsewage is discharged into rivers and lakes, large quantities of foamresult. The diluted detergent solutions often enter subsurface waterswhich ultimately feed into the underground water strata serving manycities as a source of water supply. Occasionally. these detergents turnup in sufficient quantities in tap water to cause the water to foam atthe tap.

The petrochemical industry has attempted to solve the foam problem insewage disposal plants. etc. through the development of biodegradabledetergents. It has been found that alkylaryl-based detergents are morereadily degradable by sewage bacteria it the alkyl substituent on thephenyl nucleus is of a simple. straight-chain configuration than if itis of a more complex branched chain structure. As an example, detergentcompounds in which the alkyl side chain has a structure such as: CHCH(CH CH are more likely to be bacterially digested than detergents ofthe same chemical composition but in which the isomeric alkyl radical isa more highly branched chain, such as:

CH CH CH CH3 H CH3 These biodegradable detergents are generallymanufactured by the isolation of C -C n-paraffins from mixturescontaining the paraffins utilizing molecular sieves or urea adduction,and converting the n-paraffin to an olefin-acting compound such as amonohalogenated paraffin or a mono-olefin, or by the cracking ofsaturated paraffin waxes to produce a linear olefin. These olefin-actingcompounds are then used to alkylate a mono-cyclic aromatic such asbenzene and the resultant alkylaromatic is sulfonated and neutralized toform the desired detergent.

Complete conversion of the n-paraffin to olefinacting compounds is notpossible because of undesired side reaction which occur in bothhalogenation and dehydrogenation reactions at high conversions,lessening the overall selectivity and yield. in addition, one of thecommon sources of (I -Cm paraffins, utilized in forming olefin-actingcompounds, are those C C paraftins present in the kerosene fraction ofpetroleum. The n-paraffins separated from this fraction are oftenconverted to the corresponding olefin-acting compounds withoutseparating the C,,C n-paraffin homologs from each other. As a result ofthe incomplete conver-- sion to olefin-acting compounds, there results amixture of the unconverted paraffins and the resultant olefin-actingcompounds. in prior art processes, this mixture is separated into anolefin-acting compound stream and a recycle paraffin stream. However,since the reaction product contains a complex mixture of the variousolefin-acting compound isomers along with the unconverted paraffin, thisseparation is accomplished only by exotic and intricate separationtechniques. This is particularly true in the conversion of a mixture ofthe C -C paraffin homologs to the corresponding olefinacting compounds.Here, there is an overlap in boiling points between the unconvertedparaffins and the olefin-acting compounds formed from this mixture.Present prior art processes approach this problem through utilization ofintricate separation techniques as previously mentioned, or by utilizinga narrower carbon number range in the paraffins converted. A furtherproblem present in prior art processes arises in maintaining aneutralized alkylaromatic sulfonate free from discoloration and fromexcessive amounts of inorganic salts such as sodium sulfate. Currentprocesses maintain their production of such sulfonates relatively freefrom discoloration and excessive amounts of inorganic salts throughcomplex manipulation of the operating variables such as reactiontemperature. sulfonating agent purity and strength, sulfonating agent toalkylaromatic ratio, reaction time, feed purity, and conversion. inaddition, bleaching techniques are often employed to bring the finalproduct up to color specifications.

SUMMARY OF THE INVENTION Accordingly, it is an object of this inventionto provide a new, improved process for the manufacture of alkylaromaticsulfonate detergents. Specifically, it is an object of this invention toprovide a novel means of producing alkylaromatic sulfonates containing alinear C C alkyl group derived from the corresponding n-paraffinswithout the necessity of intricate means for the separation of theunreacted paraffin. More specifically, it is an object of this inventionto provide a means for producing relatively color-free neutralizedalkylaromatic sulfonates.

in an embodiment, this invention relates to a process for producing analkylaromatic sulfonate containing a C,,C, linear alkyl group, whichcomprises the steps of: (a) separating a C C n-parafiin from ahydrocarbon mixture containing said n-paraffin; (b) monohalogenatingsaid n-paraffin, recovering from the resultant halogenated effluent,monohalogenated paraffin in admixture with unreacted n-paraffin; (c)alkylating with said monohalogenated paraffin, in admixture with theunreacted paraffin, a monocyclic aromatic to form an alkylaromaticcontaining a C,,-C,,, linear alkyl group; (d) separating, from theresultant alkylated effluent, unreacted monocyclic aromatics; (e)sulfonating said alkylaromatic in admixture with said n-paraffin to forman alkylaromatic sulfonic acid; (f) separating the resultant sulfonationmixture into an acid phase and a hydrocarbon phase containing saidn-parafiin and said sulfonic acid; (g) neutralizing the alkylaromaticsulfonic acid contained in said hydrocarbon phase to form a neutralizedalkylaromatic sulfonate in admixture with said n-paraffin; (h)separating, from the mixture of step (g), said n-paraffin and saidneutralized aromatic sulf'onate; and, (i) recycling at least a portionof said n-paraffin to said monohalogenation step.

In summary, a principal advantage of this invention resides in theability to produce relatively color-free alkylaromatic sulfonatescontaining a linear C,,C alkyl group by sulfonating an alkylaromatic,containing said alkyl group, in admixture with C C n-paraffin andneutralizing the hydrocarbon phase of the sulfonation reaction. Furtheradvantages of the invention reside in the ability to convert C,,C,,,n-paraffins to olefin-acting compounds, alkylating with such compoundsto form alkylaromatics, sulfonating the alkylaromatics and neutralizingthem, all with the reactants in admixture with unconverted n-paraff'ms,thus eliminating intermediate separation of the paraffin, with theability to operate over a wider carbon number range than has beenheretofore available from prior art processes.

DESCRIPTION OF PREFERRED EMBODIMENTS The C C n-paraffins utilized inthis invention may be obtained from any suitable source including anappropriate fraction of a straight run petroleum distillate, typicallythose in the kerosene range; the products of the Fischer-Tropschreaction, a process by which paraffinic hydrocarbons in the C -C rangeare formed by the reaction of hydrogen with carbon monoxide; thehydrogenated products of ethylene polymerization; and the hydrogenatedfatty acids which upon complete reduction. produce paraffmichydrocarbons having a straight chain configuration. Although any sourcecontaining C -C n-paraffins may be utilized in this invention, thepreferred source is a kerosene boiling range fraction boiling in therange from about C. to about 300C.

All of the foregoing enumerated n-paraffin sources have a significantamount of branched chain isomers in admixture with the n-paraffins whichmust be separated if said paraffin is to be utilized in the preparationof alkylaromatic sulfonates containing a linear alkyl group. Thesen-paraffins may be separated by any of the procedures known to the art,the exact method of separation not being critical to this invention.Such separation processes include those employing molecular sievesorbents or urea adduction. The separation processes involving molecularsieves are characterized in that the zeolite structure is a crystallinealumino-silicate containing pores of about 5 Angstroms incross-sectional diameter which are of sufiicient size to permit theentry of n-aliphatic compounds, but are not of sufficient size to permitthe entry of branched chain or cyclic compounds. As a result, when amixture containing naliphatics contacts these sieves, the linearaliphatic compounds are selectively sorbed and recovered. Theseseparation processes are well known to the art, as exemplified by US.Pat. Nos. 2,985,589; 3,274,099 and 3,310,486.

While the use of molecular sieves constitutes the preferred separationmeans, another separating agent applicable is urea, a compound whichforms an adduct or clathrate with straight chain compounds. Thisseparation is typically accomplished by mixing urea with a hydrocarbonfraction containing n-paraffins, thereby forming a crystalline adductwith the normal components, recovering the crystals, and freeing thenormal hydrocarbons by heating the crystals or by displacement with apreferentially sorbed compound such as an alcohol, aldehyde, or otheraliphatic compound containing a polar radical.

The recovered C,,C n-paraffin may be converted by known methods to oneof the known olefin-acting compounds applicable within this invention.These compounds include olefins, alcohols, ethers, esters, the latterincluding alkyl halides, alkyl sulfates, alkyl phosphates, and esters ofcarboxylic acids, with the monoolefins and monohalogenated parafiinsbeing preferred. The olefin-acting compound must be capable of providinga C C,,, straight chain alkyl group on a single aromatic nucleus, to beutilized in this invention, thus eliminating those compounds having morethan one reactive group such as polyolefins and polyhalogenatedparafiins.

Of the monohalogenated paraffins, the monochlorinated and monobrominatedare preferred. The technique of preparing such compounds by thehalogenation of the corresponding paraffin is well known in the art, andreference thereto may be had for specific details of the process. Thesehalogenation techniques generally involve reacting the paraffin undercarefully controlled conditions to insure monohalogenation and minimizethe formation of polyhalides. The reactions are generally carried out bycontacting bromine or chlorine and excess normal paraffin. Catalyticagents, such as diffused sunlight, light of a specific wavelength, i.e.artificial ultraviolet light, or trace amounts of iodine are oftenemployed. The resultant monohalogenated paraffins consist of a mixtureof the various linear isomers with the internal halogenated isomersbeing more prevalent.

'l he other preferred olefin-acting compounds, the linear mono-olefins,may be derived by methods known to the art such as cracking of longchain saturated paraffiris, dehydrohalogenation of the aforementionedmonohalogenated paraffins or by the selective dehydrogenation of thecorresponding linear paraffms. The selective dehydrogenation of then-paraffms yields a mixture of the corresponding internal olefin isomersand is typically effected by processes which include contacting then-paraffin with a dehydrogenation catalyst containing a support havingan alkali metal compound thereon and promoted with a metal or metalcompound selected from the metals of the Groups VI and VIII of thePeriodic Table. Other catalysts suitable for the dehydrogenation ofstraight chain paraffins to form straight chain mono-olefins compriserefractory spacing agents or carriers selected from the group consistingof activated alumina, magnesia, silica and diatomaceous earth, and minoramounts of the metal and/or metallic oxides of elements selected frommembers of Groups IVB, VB, and VIB, Group VIII, and Group IB of thePeriodic Table (E. H. Sargent & C0,, 1964) and include titanium,zirconium. hafnium, and vanadium, niobium, and tantalum; chromium,molybdenum, and tungsten; iron, cobalt, nickel, platinum, palladium,copper, silver, and the like, including mixtures of the foregoing.Usually nonacidic catalysts are desirable since they minimize the amountof isomerization of the n-paraffins or resulting mono-olefins to theirbranched chain isomers.

Especially preferred are those processes which contact the n-paraffinwith a catalytic composite of alkalizcd alumina, a Group VIII metalliccomponent, and a metallic component of arsenic, antimony, bismuth, andcompounds thereof, at dehydrogenating conditions including a temperatureof about 400C. to about 600C, operating pressures of about 10.0 psig. toabout 100 psig., a mole ratio of hydrogen to liquid hydrocarbon chargeof less than :1 and a liquid hourly space velocity above 12.0.Particularly preferred are those catalysts which are catalyticcomposites of alumina containing from about 0.01% to about 1.5% byweight lithium, from about 0.05% to about 5.0% by weight of a Group VIIInoble metal component and a metallic component selected from the groupconsisting of arsenic, antimony, bismuth, and compounds thereofin anatomic ratio to said Group VIII component of from about 0.20 to about0.50.

Typically, these dehydrogenation processes have conversions from about5% to about 25% and selectivities greater than 90%. Higher conversionsare possible but not practical because of undesired side reactions whichlower selectivity. The resultant dehydrogenation effluent may beseparated to recover the linear monoolefins from the unreactedn-paraffins, but since the subsequent alkylation, Sulfonation, andneutralization are to take place in the presence of a C -C paraffin, itis more practical and feasible to perform these steps in the presence ofthe undehydrogenated n-paraffin, thus eliminating intermediateseparation. This same principle applies to those processes wherein theparaffin is first monohalogenated. Thus, the unreacted nparaffinremaining after the formation of the olefinacting compound is readilyrecoverable after the sulfonation and neutralization and may be recycledand con verted to additional olefin-acting compound.

The aromatic reactants which are alkylated with the olefin-actingcompounds to yield a mono-alkylate include the mono-cyclic aromaticsselected from the group consisting of benzene, toluene, xylene,ethylbenzene, diethylbenzene, phenol, and mono-nitrobenzene. Thealkylation reaction is effected in the presence of a suitable catalystcapable of promoting the condensation reaction between the olefin-actingcompound and the monocyclic aromatic. Such catalysts are generally aninorganic material characterized as an acid-acting compound whichcatalyzes the alkyl transfer reaction involved. Such inorganic compoundsinclude certain mineral acids such as sulfuric acid containingpreferably less than 10% water; hydrofluoric acid of at least 83%concentration and containing less than 10% water; liquefied anhydroushydrogen fluoride; anhydrous aluminum chloride or aluminum bromide;boron trifluoride, preferably utilized in admixture with concentratedhydrofluoric acid; and other acid-acting catalysts, particularly of theFriedel-Crafts class of metal halides when the Olefin'acting compound isthe monohalogenated paraffin. Such alkylation reaction conditions andprocedures are well known to the art and reference may be made theretofor specific details. Preferred alkylation conditions includetemperatures of about -20C. to about 40C., a molar excess of aromatic toolefin-acting compound and a molar ratio of catalyst to olefin-actingcompound of 0.0l or greater.

The alkylation reaction effluent is separated to recover the organicportion from the used catalyst. When utilizing a molar excess ofaromatic, the olefin is essentially completely consumed and the reactantproduct is essentially the desired mono-alkylate. The unreacted aromaticis separated from the aromatic-alkylaromatic nparaffin mixture, andrecycled to the alkylation reaction, by methods known to the art,including distillation and solvent extraction via sulfolane, glycol,etc. Separation of the unreactcd aromatic is effected to avoidsubsequent Sulfonation thereof.

Sulfonation conditions include those well known to the art. The amountof n-paraffin present, the essence of this invention, is that amountrequired to remove the alkylaromatic sulfonate from the acid, leavingthe color-bodies in the acid phase. This amount typically is in therange of about 20% to about 96 weight of the n-paraffin-olefin-actingcompound mixture passed to the alkylation zone. This concentrationincludes that concentration of unconverted n-paraffins present in themonohalogenation or dehydrogenation reaction effluent. It is to beemphasized that the C -C n-paraffin present in the Sulfonation andneutralization steps need not be carried over" from the previous stepsand may be commingled with pure alkyl-aromatic being passed to theSulfonation reaction.

Sulfonation conditions include a temperature of abour 20C. to about C.and such reactions may be conducted continuously or batchwise. Thehydrocarbon feed may be given an acid wash with sulfuric acid belowsulfonating strength to remove impurities present in the feed.Sulfonating agents which may be utilized are essentially anhydroussulfuric acid, relatively weak oleum, or even free sulfur trioxide. Suchagents are preferably used in excess of that required for completesulfonation. Specifics regarding sulfonation of alkylaromatics are wellknown to the art and may be obtained by reference thereto, An acid phasecontaining color bodies and a hydrocarbon phase containing therelatively color-free alkylaromatic sulfonic acid, are separated fromthe resulting sulfonation product.

The color bodies formed in the sulfonation reaction are the products notonly of reactions involving impurities present in the hydrocarbon feedand/or sulfonating agent but also of undesirable side reactions betweenthe principal reactants. These side reactions can be minimized but noteliminated by manipulation of operating variables. lnevitably, somecolor bodies are formed which ultimately must be removed. Since theprocess of this invention selectively removes the alkylaromaticsulfonate from the color bodies formed during sulfonation, minor upsetsin operating variables will not have as adverse an effect upon productquality as heretobefore experienced. in other words, this process is notas sensitive to operating variables which result in the inclusion ofcolor bodies in the final product, as the prior art processes.

The alkylaromatic sulfonic acids present in the hydrocarbon phaseremoved from the sulfonation reaction are neutralized to form awater-soluble alkylaromatic sulfonate detergent, preferably, with analkaline compound of potassium, sodium, lithium or magnesium with sodiumbeing especially preferred. These bases are preferably utilized inaqueous solutions and include aqueous solutions of the correspondinghydroxides and carbonates. Other basic compounds which may be utilizedin this invention include ammonia and the basic ammonium compounds andthe lower molecular weight amines. Of the neutralization conditions,temperature is the most important and should be maintained at below 70C.to avoid decomposition reactions. Other neutralization conditions andtechniques are well known to the art and reference may be had theretofor further particulars.

The neutralized sulfonic salts may be recovered by any of those methodsknown to those trained in the art including steam distillation of theneutralized mixture, spray drying, drum drying, etc. Typically, thealkylaryl sulfonate is neutralized with aqueous sodium hydroxide, thusextracting the water soluble neutralized sulfonic salt from then-paraffin phase to the aqueous phase. The resultant aqueous solution isdried by methods known to the art thereby recovering dry, inorganicsalt-free, colorless detergent. The unreacted n-paraffin is readilyseparated from the final neutralization product since it forms asaltfree upper phase distinct from the aqueous lower phase. Thus, then-paraffin recov ered from this step may be recycled to be admixed withthe alkylaromatic being passed to the sulfonation step, or, moretypically, back to the step wherein the nparaffins are first convertedto olefin-acting compounds such as the monohalogenated paraffins ormono-olefins.

The presence of a C,,C,,, n-paraffin in the alkylation, sulfonation andneutralization steps serves a multifold purpose. Not only does it createa process not requiring intermediate separation of the olefin-actingcompound and its paraffin derivative, but it also provides a processmore readily operable in the sulfonation step that produces a relativelycolor-free product. The physical presence of the paraffin in these stepsserves, first, as a heat sink for the exothermic alkylation,sulfonation, and neutralization reactions, and, secondly, as a diluentto insure uniformity within the reaction, thus rendering it moreamenable to agitation. Thirdly, the alkylaromatic sulfonic acids formedin the sulfonation reaction are removed from the acid phase into thenparaffin phase, leaving the majority of the color bodies in the acidphase. The import of this feature is obvious. First of all, the presenceof the alkylaromatic sulfonic acids formed in the sulfonation reactionwithin the nparaffin phase reduces the amount of base necessary toneutralize the sulfonic acids heretobefore available in processeswherein the spent sulfonating agent and sulfonate are neutralizedtogether; secondly, it renders a sulfonate upon neutralization free fromthe inorganic salt of the sulfonating agent. Most importantly, the greatmajority of the color-bodies formed within the sulfonation reactionremain in the acid phase, yielding a relatively color-free paraffinphase which upon neutralization, yields a detergent with much improvedcolor characteristics than have heretobefore been available to the artother than through the use of extraneous exotic purification methods.

The process of the present invention is further described in thefollowing illustrative example which is, however, not presented for thepurpose of limiting the scope of the invention, but in order to furtherillustrate the embodiments of the present process.

EXAMPLE A straight-run petroleum fraction (recovered from a Michigancrude oil) boiling within the range of from about l to about 225C. andhaving the following composition, according to the general classes ofthe hydrocarbons present:

is resolved into the following two classes of components: lstraight-chain or normal paraffins and (2) a mixture of isoparaffinicand cyclic hydrocarbons. The recovered normal paraffins are thereafterdehydrogenated to their mono-olefin analogs and these are thereafterused to alkylate benzene to form phenylsubstituted normal alkanes. Then-paraffin-benzene alkylate mixture is sulfonated, followed byneutralization of the hydrocarbon portion to yield the alkylarylsulfonate salt, a water-soluble, biodegradable or soft" detergent.

In the first step of the reaction sequence, the normal paraffins in thestraight-run fraction are separated therefrom by contacting the mixturewith pelleted alumino-silicate molecular sieves which selectively sorbthe normal paraffinic components of the mixture and leave a nonsorbedraffinate consisting of isoparaffins and the cyclic hydrocarbons presentin the fraction. For effecting this separation, the straight-runkerosene fraction is poured at room temperature (25C.) into a verticalcolumn packed with the molecular sieve pellets; the resulting column is5 ft. in length and contains 3.8 ft. of the pellets, each having adimension of approximately Vs inch X Va inch. A raffinate effluent fromthe bottom of the column of molecular sieves consists of n-paraffin-freehydrocarbons. The normal paraffin components of the kerosene fraction(about 37% of the total volume of kerosene) remain within the column,sorbed on the molecular sieve particles. The residual raffinate retainedon the surface of the pellets is washed from the column by pumpingisopentane into the top of the column and draining the effluent from thebottom. Any isopentane remaining on the pellet surfaces is separatedfrom the recovered n-paraffin sorbate product by distillation. Raffinatecontained in the wash effluent is recovered as bottoms on distillationof the wash effluent.

After completely draining the column of isopentane wash, the n-paraffinssorbed from the kerosene feed stock are desorbed by filling the columnwith liquid npentane at 25C., allowing the n-pentane to displace by themass action effect the kerosene-derived n-paraffins present in the poresof the molecular sieve particles, and after 10 minutes, the liquidsurrounding the sorbent particles is drained into a distillation flask.The column is again filled with n-pentane and after standing for anadditional 10 minutes, the liquid in the column is drained into a seconddistillation flask. Distillation of the n-pentane from the effluentstream in each case left a residue of kerosene n-paralfins (98.5 percentnormal components ofC C chain length) in each flask, 96 percent of thetotal recovered sorbate being in the first flask. The resultantn-paraffins are then further fractionated to obtain a C (dodecane)fraction containing 99.5% dodecane and 0.6% isomers.

The recovered C n-paraffin is thereafter dehydrogenated by passing theparaffin in admixture with hydrogen at an 8:1 hydrogen to paraffin moleratio to a small pilot plant reactor maintained at isothermal conditionsof 470C. and 10 psig. The feedstock charge rate (in terms of liquidhourly space velocity) is 32 volumes of paraffin charge per volume ofcatalyst per hour. The catalyst packed in the pilot plant reactor is anarseniccontaining lithiated platinum catalyst containing 0.75 wtT/rplatinum on alumina, 0.47 arsenic to platinum mole ratio and 0.5 wt.%lithium. The product eflluent is cooled and normal gaseous componentsremoved to provide a liquid product containing 11.1 wt.% dodecene. 87.8WtT/ dodecane. and small amounts of diolefins and aromatics.

This liquid product containing the C mono olefin is mixed with 1() molarproportions of benzene to C mono-olefin and the hydrocarbon mixturecooled to (1C. as hydrofluoric acid of 97.5% concentration is added withstirring, to provide a weight ratio of acid to olefins of 1.5. Thismixture is maintained and agitated for 1.5 hours. maintaining atemperature of about 0C. The mixture is then allowed to settle and theupper hydrocarbon phase is withdrawn and washed with dilute caustic andthen distilled to remove excess benzene. The remainder consistsessentially of 16.8 wt.7( dodecyl benzene, 83.1 wtf'i C n-paraffin andtrace amounts of unreactcd olefin. A portion of this material is furtherdistilled to remove these paraffins. etc. to produce an essentially puredodecylbenzene.

The remaining liquid product containing the dodecane and dodecylbenzenemixture is placed in an agitated flask maintained at 15C. by a constanttemperature bath as fuming sulfuric acid containing sulfur trioxide isgradually added over a period of two hours with stirring to provide afinal weight ratio of acid to dodecylbenzene of 1.25. This mixture ismaintained at 15C. with agitation for an additional 1.5 hours to insureessentially complete sulfonation of the alkylaromatic. The mixture isthen allowed to settle and two separate layers form. a black acid lowerphase and a very light yellow-colored top hydrocarbon phase. The

top hydrocarbon phase is passed into an equal volume of water, alsomaintained at 15C. with the resultant mixture being completelycolorless. The mixture is maintained at 15C. and neutralized to aphenolphthalein end point with a 10 wt.% aqueous solution of sodiumhydroxide. The mixture is allowed to settle to form an upper hydrocarbonphase and a lower aqueous phase containing the neutralizeddodecylbenzene sulfonate. This lower phase is separated and dried toyield an essentially all white detergent product essentially free frominorganic salts. A portion of the hydrocarbon phase is also evaporated,leaving little residue, indicating no appreciable amounts ofalkylaromatic sulfonate to be present. The lower acid phase is alsoneutralized and evaporated to dryness to form a dark, discolored solid.This solid is extracted with ethanol, with the ethanol upon evaporationleaving essentially no residue, thus indicating all of the alkylaromaticsulfonate to be in the original hydrocarbon phase present upon thecompletion of the sulfonation reaction.

The dodecylbenzene obtained by the removal of the admixed dodecane wassulfonated in the same manner as the dodecane-dodecylbenzene mixtureexcept that upon completion of the reaction, a single dark-brownsolution resulted which upon neutralization and drying yielded a yellowdodecylbenzene sulfonate-sodium sulfate mixture.

EXAMPLE 11 A run somewhat similar to Example I is performed utilizingthe entire C ,C nparaffin mixture. This mixture of homologs isdehydrogenated, the resultant olefins alkylated, the resultant alkylatedbenzene sulfonated and the sulfonated alkylaromatic neutralized in thesame manner as the dodecane-dodecylbenzene mixture of Example 1. Theresultant neutralized sulfo nate recovered from the hydrocarbon phase ofthe sulfonation reaction is a white, inorganic salt-free detergent ofequivalent quality as that formed in Example I. The unconvertedparaffims are dried and blended with the C C, paraffin passed to thedehydrogenation reaction.

CONCLUSIONS From the foregoing specification and examples, thebeneficial import of the process of this invention is readily apparentto those trained in the art. This process offers a means of converting C,C n-paraffins and a monocyclic aromatic into an alkylaromatie sulfonatecontaining a C -C linear alkyl group without involving the intermediateseparation of the n-paraffin. Further, this process makes possible theproduction of alkylaromatic sulfonates free from inorganic salts, thusalleviating the necessity of extracting such salts from the finalproduct heretofore practiced in the art. Most importantly. this processoffers a means for producing alkyl-aromatic sulfonates free fromundesirable colorbodies without involving sophisticated bleaching andseparation techniques.

We claim as our invention:

1. A process for producing an alkylaromatic sulfonate containing a C Clinear alkyl group which comprises the steps of:

a. monohalogenating a C ,C n-paraftin by contacting bromine or chlorinewith an excess of said n-paraffin to form a CgC g linear monohalogenatednparaffin. recovering from the resultant monohalogenation elflucnt saidC C linear monohalogenated paraffin in admixture with unreacted C Cn-paraffin, said unreacted C,,C n-paraffin being present in an amount offrom about to about 96 wt.% of C,,C monohalogenated paraffin;

b. alkylating a monocyclic aromatic selected from the group consistingof benzene, lower alkyl substituted benzene, phenol andmono-nitrobcnzene with said C -C, linear monohalogenatcd nparafiin inadmixture with the unreacted C -C n-paraffin to form an alkylaromaticcontaining a C ,C linear alkyl group;

c. separating unreacted monocyclic aromatic from the resultant effiuentof step (b) which contains said unreacted monocyclic aromatic, C C,,.linear alkylaromatic, and C,,C n-paraffin;

d sulfonating the alkylaromatic of step (c) in admixture with the C -Cn-paraffin of step (c), with an acidic sulfonating agent to form analkylaromatic sulfonic acid, said acidic sulfonating agent beingselected from the group consisting of sulfuric acid and oleum and beingpresent in an amount in excess of the stoichiometric quantity requiredto sulfonate said alkylaromatic;

e. separating the resultant sulfonation mixture into an acid phasecontaining excess acidic sulfonating agent and a hydrocarbon phasecontaining said C,,-C n-paraffin and said alkylaromatic sulfonic acid;

f. neutralizing the hydrocarbon phase by admixing that phase with anaqueous solution of a base selected from the group consisting of ammoniaand the hydroxides and carbonates of sodium, potassium, lithium andmagnesium to form a swatersoluble neutralized alkylaromatic sulfonate;

g. forming a hydrocarbon phase containing unreacted C,,-C n-paraffin,and an aqueous phase containing water-soluble neutralized aromaticsulfonate;

h. separating the phases formed in step (g);

i. recovering water-soluble alkylaromatic sulfonate from the aqueousphase; and,

j. recycling at least a portion of the separated unreacted C Cn-paraffin of step (g) to monohalogenation step (a).

2. The process of claim 1 further characterized in that said monocyclicaromatic is benzene, said sulfonating agent is oleum and the hydrocarbonphase is neutralized with an aqueous solution of sodium hydroxide.

1. A PROCESS FOR PRODUCING AN ALKYLAROMATIC SULFONATE SONTAINING AC9-C18 LINEAR ALKYL GROUP WHICH COMPRISES THE STEPS OF: A.MONOHALOGENATING A C9-C18 N-PARAFFIN BY CONTACTING BROMINE OR CHLORINEWITH AN EXCESS OF SAID N-PARAFFIN TO FORM A C9-C18 LINEARMONOHALOGENATED N-PARAFFIN, RECOVERING FROM THE RESULTANTMONOHALOGENATION EFFLUENT SAID C9-C18 LINEAR MONOHALFOENATED PARAFFIN INADMIXTURE WITH UNREACTED C9-C18 N-PARAFFIN, SAID UNREACTED C9-C18N-PARAFFIN BEING PRESENT IN AN AMOUNT OF FROM ABOUT 20 TO ABOUT 96 WT.%OF C9-C18 MONOHALOGENATED PARAFFIN, B. ALKYLATING A MONOCYCLIC AROMATICSELECTED FROM THE GROUP CONSISTING OF BENZENE, LOWER ALKYL SUBSTITUTEDBENZENE, PHENOL AND MONO-NITROBENZENE WITH SAID C9-C18 LINEARMONOHALOGENATED N-PARAFFIN IN ADMIXTURE WITH THE UNREACTED C9-C18N-PARAFFIN TO FORM AN ALKYLAROMATIC CONTAINING A C9-C18 LINEAR ALKYLGROUP. C. SEPARATING UNREACTED MONOCYCLIC AROMATIC FROM THE RESULTANTEFFLUENT OF STEP (B) WHICH CONTAINS SAID UNTREATED MONOCYCLIC AROMATIC.C9-C18 LINEAR ALKYLAROMATIC, AND C9-C18 N-PARAFFIN, D. SULFONATING THEALKYLAROMATIC OF STEP (C) IN ADMIXTURE WITH THE C9-C18 N-PARAFFIN OFSTEP (C), WITH AN ACIDIC SULFONATING AGENT TO FORM AN ALKYLAROMATICSULFONIC ACID, SAID ACIDIC SULFONATING AGENT BEING SELECTED FROM THEGROUP CONSISTING OF SULFURIC ACID AND OLEUM AND BEING PRESENT IN ANAMOUNT IN EXCESS OF THE STOICHIOMETRIC QUANTITY REQUIRED TO SULFONATESAID ALKYLAROMATIC, E. SEPARATING THE RESULTANT SULFONATION MIXTURE INTOAS ACID PHASE CONTAINING EXCESS ACIDIC SULFONATING AGENT AND AHYDROCARBON PHASE CONTAINING SAID C9-C18 N-PARAFFIN AND SAIDALKYLAROMATIC SULFONIC ACID: F. NEUTRALIZING THE HYDROCARBON PHASE BYADMIXING THAT PHASE WITH AN AQUEOUS SOLUTION OF A BASE SELECTED FROM THEGROUP CONSISTING OF AMMONIA AND THE HYDROXIDES AND CARBONATES OF SODIUM,POTASSIUM, LITHIUM AND MAGNESIUM TO FORM A SWATER-SOLUBLE NEUUTRALIZEDALKYLAROMATIC SULFONATE, G. FORMING A HYDROCARBON PHASE CONTAININGUNTREATED C9C18 N-PARAFFIN, AND AN AQUEOUS PHASE CONTAINING WATERSOLUBLENETURALIZED AROMATIC SULFONATE, H. SEPARATING THE PHASES FROM IN STEP(G): I. RECOVERING WATER-SOLUABLE AROMATIC SULFONATE FROM THE AQUEOUSPHASE, AND. J. RECYCLING AT LEAST A PORTION OF THE SEPARATED UNTREATEDC9-C18 PARAFFIN OF STEP (G) TO MONOHALOGENATION STEP (A).
 2. The processof claim 1 further characterized in that said monocyclic aromatic isbenzene, said sulfonating agent is oleum and the hydrocarbon phase isneutralized with an aqueous solution of sodium hydroxide.